Specific aims of the Cooperative Clinical Trials in Transplantation are to induce donor specific unresponsiveness in living related kidney transplant patients, as well as to determine the safety and benefit in terms of lessened rejection and improved graft survival from the administration of donor bone marrow cells to recipients of cadaveric renal transplants. An improved understanding of methods in inducing tolerance in clinical transplantation will allow increased success rates which will be of direct benefit to many patients with end stage organ failure. The induction of allogenieic tolerance and the basic principles involved in tolerance induction may theoretically be of benefit also to those patients suffering from autoimmune disease.